My point in the last post was that Calvinists do not limit the Atonement in power, sufficiency, or scope. That may have been a little misleading, but what I tried to point out was that unbelievers benefit from the death of Christ 'for the sake of the elect'.
Here's something Jesus said:
"And if those days had not been cut short, no human being would be saved. But for the sake of the elect those days will be cut short." (Mat 24:22)
This quote comes in the context of Jesus explaining to His disciples the coming destruction of Jerusalem. And He reminds them in this verse that without God holding back the destruction that was to come, no human being would be saved, or, left alive. But for the sake of the elect, who have been definitely bought and sealed with Christ's atoning death, the end would come quickly.
So the blessing of the preservation of humanity comes as a result of Christ's atonement for the sins of His elect. But there are other benefits that come 'for the sake of the elect' as well. What are these blessings? Everything.
Any good thing that exists is for the enjoyment of the elect, but the non-elect participate in these temporal blessings as well. It rains on the just and the unjust.
So the question does come down to scope in a sense, not in the sense of who benefits from Christ's death, but who benefits spiritually form Christ's death. Calvinists affirm, along with Arminians,that Christ's death pardons the sins of only those who believe and repent. Limited Atonement should not even really be an issue in Arminian/Calvinist debates. The issue is God's purpose of grace. Calvinists believe that the election of individual sinners to salvation is the God's purpose of grace. This purpose is accomplished through the Atonement for their sins.